16 February 2007
Vol 315, Issue 5814

About The Cover

Cover image expansion

COVER Tectonic fractures within the Candor Chasma region of Valles Marineris, Mars, retain a ridgelike morphology as the surrounding bedrock erodes away. Such findings offer clues about past fluid flow and geochemical conditions within the subsurface. The image is about 1 kilometer across; illumination is from the upper left. See page 983. Image: Lunar and Planetary Laboratory, University of Arizona/JPL/NASA